@unpublished{TUW-241972, author = {Retscher, G{\"u}nther}, title = {Differential Wi-Fi - A New Approach for Wi-Fi Positioning Using Lateration}, year = {2015}, keywords = {Wi-Fi, differential positioning, lateration}, note = {invited; talk: IUGG 2015 General Assembly, Prag; 2015-06-22 -- 2015-07-02} }